This invention relates generally to hyperspectral imagers, and, more particularly, to a hyperspectral imager design that is easier and less costly to fabricate, more compact in physical size and mass, and superior in spectral and spatial imaging quality than previous designs.
A hyperspectral imager is a known device that is commonly used to examine the spectral, or wavelength dependent, content of an object or scene. (Hyperspectral imagers are also referred to as imaging spectrometers.) In a hyperspectral imager light emitted or reflected by a given object or scene is imaged onto the entrance of a spectrometer, usually a slit element that transmits a single line image of the object or scene. The spectrometer in turn re-images this light to another location while dispersing this light according to its wavelength in a direction orthogonal to the orientation of the slit element, where it can readily be observed or recorded. In this manner, each slice of the object or scene is decomposed into a two-dimensional data array, and by scanning the object or scene in line-by-line increments, a three-dimensional data cube is formed.
Because every material has a unique spectral signature, the hyperspectral imager has become a very useful scientific tool in a broad range of scientific and industrial applications including, but not limited to, the monitoring of regional and global environmental conditions, the identification of both airborne and terrestrial objects and in surveillance imagery for remote sensing applications, assessment of unknown substances in forensic applications, the precise characterization of color spectra in colorimetry, and even the assessment and irrigation scheduling of crops in the farming industry.
Current optically fast hyperspectral imager designs are either too large in size for many applications, including but not limited to, unmanned aircraft surveillance, and forensic fieldwork.
It is therefore an object of this invention to provide a hyperspectral imager design that is compact in physical size.
It is a further object of this invention to provide a hyperspectral imager design that is simple in mechanical design with reduced alignment tolerances.
It is a further object of this invention to provide a hyperspectral imager design that is low in cost to fabricate.
It is a further object of this invention to provide a hyperspectral imager design that provides a high degree of spatial and spectral image quality that is relatively free of spatial and spectral image distortions.
It is a still further object of this invention to provide a hyperspectral imager design that operates over multiple bands of wavelength, forming a separate spectral image for each band.